After the receiving?end AC fault occurs in the multi?infeed HVDC system, it is easy to cause simultaneous commutation failure of multiple DCs, resulting in a large quantity of power shortage and active power fluctuation. In order to achieve effective suppression of grid power fluctuation after the receiving?end AC faults in the multi?infeed HVDC transmission system, from the perspective of AC/DC interaction strength and the critical nodes and lines of active power, a siting method of the energy storage system is proposed for suppressing power fluctuation of the AC system after commutation failure is proposed. Firstly, the candidate areas are determined according to the multi?infeed interaction factor(MIIF), and then the candidate sites are determined by the multi?infeed effective short circuit ratio(MIESCR). Finally, the specific location of the energy storage system is determined by the active power fluctuation rate of the whole network(APFRWN). The simulation results are verified in PSCAD based on the modified IEEE?39 bus system. The location method of the energy storage system proposed in this paper can effectively reduce the power fluctuation caused by DC commutation failure caused by AC fault at the receiving end and improve the stability of the AC system.